^^Stress, strain, modulo di Young.

ref:  Storia.

Situazione: cilindro tirato o pressato assialmente

Ut tensio sic vis. L'allungamento causa la forza elastica.

Strain, stress, modulo di Young.

strain, ε = ΔL/L, allungamento relativo.

stress, sforzo, tensione

it: tensione interna (o sollecitazione interna o sforzo)

en: stress (force per unit area)

modulo di Young.

uniaxial stress

tensile or compressive stress in one direction and no stress in the other directions

modulus

is the diminutive of the Latin term modus which means measure

Links

1. Ut tensio sic vis.

2. Stress, strain, modulo di Young. Storia.

3. L'allungamento assottiglia l'elastico. Effetto Poisson.
4. Tensione meccanica.

5. Links inet

6. wp/Young's_modulus
7. wp/Elastic_modulus
8. wp/Teoria_della_plasticità
9. tecnologiameccanica/teoria-deformazione-plastica/dp_teoria-tensione-di-flusso

Approfon

Strain stress  VS  stress strain

scelgo: l'ordine della formula, nel senso

stress in funzione di strain,  l'allungamento causa la forza.

Talk

Titolo

1. stress, strain
   c: originale
2. Strain, stress, modulo di Young.
   c: 18_7_2020. Ho unito qui modulo di Young.

schey's equation

Y is the average flow stress of the material

flow stress    sforzo di flusso plastico

Assumption

stres strain related by known constitutive equations.

constitutive equations

relate stress strain

• elastic deformation: simpler
• permanent deformation: complicated

The applied loads can cause

• elastic deformation
• permanent deformation: plastic flow, fracture, phase change, etc.

wp/Plasticity_(physics)

wp/Stres-strain_analysis | Analisi_delle_sollecitazioni

Stress-strain_curve (Yield curve (physics))

Uniaxial stress

A linear element of a structure is one that is essentially one dimensional and is often subject to axial loading only.

When a structural element is subjected to tension or compression its length will tend to elongate or shorten, and its cross-sectional area changes by an amount that depends on the Poisson's ratio of the material.

In engineering applications, structural members experience small deformations and the reduction in cross-sectional area is very small and can be neglected, i.e., the cross-sectional area is assumed constant during deformation.

For this case, the stress is called engineering stress or nominal stress and is calculated using the original cross section.

σ_e = P/A_o

P is the applied load

A_o is the original cross-sectional area.

In some other cases, e.g., elastomers and plastic materials, the change in cross-sectional area is significant. For the case of materials where the volume is conserved (i.e. Poisson's ratio = 0.5), if the true stress is desired, it must be calculated using the true cross-sectional area instead of the initial cross-sectional area, as:

σ_true = ( 1 + ε_e ) ( σ_e )

ε_e   nominal (engineering) strain

σ_e   nominal (engineering) stress.

The relationship between true strain and engineering strain is given by

ε_true = ln ⁡ ( 1 + ε_e )

In uniaxial tension, true stress is then greater than nominal stress. The converse holds in compression.